Automated transmissions are known from automotive technology. Such transmissions can be operated inter alia in an automatic mode, in which the operation of the transmission is governed by the transmission control system. It is also known that a so-termed manual mode is available in which, the driver can manually select a higher or a lower gear by actuating a tip key.
During the automatic mode, under certain conditions a so-termed rolling function or coasting function can be activated by the transmission control system in order to thereby save fuel. When the rolling function is activated the drive-train is opened and the drive motor is operated in the idling mode. The motor can also be switched off in order to further reduce fuel consumption when the coasting function is activated. As soon as the conditions required for activating the rolling function or the coasting function are no longer being met, the rolling or coasting function is automatically terminated by the transmission control system.
For example, from the document DE 102 21 701 A1 a control method for motor vehicles with an automated clutch device is known. If no brake or accelerator pedal actuation has taken place for a predetermined time interval, a coasting phase is activated automatically. As soon as the control system detects that one of the conditions required for this is no longer being met, the coasting phase is automatically terminated. After the end of the coasting phase, the control system transmits a rotational speed parameter or a torque parameter in order to regulate the internal combustion engine to a desired speed. As soon as the control system determines that the rotational speeds of the motor and the transmission are synchronized, the clutch is automatically engaged again.
From the document DE 10 2007 035 426 A1 a display device and an operating method for a motor vehicle with a drive-train are known, wherein the display device signals the drive situation, for example the coasting situation. In this way the driver can be assisted to make use of the energy-efficient coasting operation as often as possible.
The known methods have the disadvantage that the coasting function can only be activated or deactivated automatically, so the attempt is made to produce the prerequisites for activating or deactivating the coasting function. The driver has no means for direct manual intervention. Furthermore, in the automatic mode, when the coasting function or the rolling function has ended, the driver has no way to influence the subsequent shifting strategy of the transmission control system.